Method for selective recovery of PET-usable quantities of [18 F] fluoride and [13 N] nitrate/nitrite from a single irradiation of low-enriched [18 O] water

Abstract

A process for simultaneously producing PET-usable quantities of [ 13 N]NH 3 and [ 18 F]F - for radiotracer synthesis is disclosed. The process includes producing [ 13 N]NO 2 - /NO 3 - and [ 18 F]F - simultaneously by exposing a low-enriched (20%-30%) [ 18 O]H 2 O target to proton irradiation, sequentially isolating the [ 13 N]NO 2 - /NO 3 - and [ 18 F]F - from the [ 18 O]H 2 O target, and reducing the [ 13 N]NO 2 - /NO 3 - to [ 13 N]NH 3 . The [ 13 N]NH 3 and [ 18 F]F - products are then conveyed to a laboratory for radiotracer applications. The process employs an anion exchange resin for isolation of the isotopes from the [ 18 O]H 2 O, and sequential elution of [ 13 N]NO 2 - /NO 3 - and [ 18 F]F - fractions. Also the apparatus is disclosed for simultaneously producing PET-usable quantities of [ 13 N]NH 3 and [ 18 F]F - from a single irradiation of a single low-enriched [ 18 O]H 2 O target.

We claim: 
     
       1. An apparatus for simultaneous quantitative production and sequential recovery of [ 13  N]NH 3  and [ 18  F]F - , comprising: a proton source for providing a beam of protons,   a target cell containing low-enriched [ 18  O]H 2  O target water for irradiation by said proton beam, anion separation means, serially connected to the target cell, through which said target water may be passed for removing [ 13  N]NO x   -  and [ 18  F]F -  from the target water,   [ 18  F]F -  eluting means, serially connected to an input of the anion separation means, by a valving means comprising a first eluant reservoir including a first eluant for selective elution of [ 18  F]F -  from the anion separation means as a collectable [ 18  F]F -  fraction, and   [ 13  N]NO x   -  eluting means, serially connected to an input of the anion separation means, by a valving means comprising a second eluant reservoir including a second eluant for selective elution of [ 13  N]NO x   -  from the anion separation means as a collectable [ 13  N]NO x   -  fraction means for separately and sequentially connecting each of said [ 18  F]F -  eluting means and said [ 13  N]NO x   -  eluting means to said input of said anion separation means, whereby exposure of low-enriched [ 18  O]H 2  O target water in the target cell to proton irradiation simultaneously produces [ 13  N]NO x   -  and [ 18  F]F -  in quantitatively recoverable amounts usable for radiotracer synthesis for PET imaging.   
     
     
       2. The apparatus of claim 1, further comprising a target water recovery reservoir, serially connected to an output of the anion separation means, such that target water can be recovered once [ 13  N]NO x   -  and [ 18  F]F -  have been removed. 
     
     
       3. The apparatus of claim 1, wherein the target cell is further adapted to receive proton irradiation from at least one proton beam having a beam energy of between about 10 MeV and about 30 MeV. 
     
     
       4. The apparatus of claim 1, wherein the anion separation means comprises an anion exchange column containing particulate anion exchange resin having quaternary ammonium functional groups having the formula: ##STR2## wherein X is a polymeric support resin and R 1 , R 2 , R 3 , and R 4  are independently selected from the group consisting of hydrogen, and alkyl groups having 1 to 4 carbons. 
     
     
       5. The apparatus of claim 4, wherein the functional groups have the formula:   X--CH.sub.2 --N--(CH.sub.3).sub.3,     wherein X is a polymeric support resin.   
     
     
       6. The apparatus of claim 1, wherein the [ 18  F]F -  eluting means includes the first eluant as aqueous 0.01M K 2  CO 3 . 
     
     
       7. The apparatus of claim 1, wherein the [ 13  N]NO x   -  eluting means includes the second eluant as aqueous 1N HCl. 
     
     
       8. The apparatus of claim 1, further comprising: basifying means, serially connected to an output of the anion separation means for rendering the [ 13  N]NO x   -  fraction alkaline to yield a basic [ 13  N]NO x   -  fraction, and   reducing means, serially connected to an output of the basifying means, for reducing the basic [ 13  N]NO x   -  fraction to yield collectable [ 13  N]NH 3 .   
     
     
       9. The apparatus of claim 8, wherein the basifying means includes a strong base. 
     
     
       10. The apparatus of claim 9, wherein the strong base includes aqueous 2N NaOH. 
     
     
       11. The apparatus of claim 8, wherein the reducing means includes DeVarda's alloy.